#validation.

You are a regex expert. I need a regular expression to match: [describe what you need to match, e.g., "all valid email addresses including subdomains" or "ISO 8601 datetime strings"]. Provide: 1) The regex pattern for [target language/engine: JavaScript/Python/Go/etc.], 2) A visual breakdown of each component of the pattern using a table (token | meaning | example match), 3) A list of strings it WILL match, 4) A list of edge cases it will NOT match (and why), 5) Any known caveats or performance concerns with this pattern, 6) A function wrapper in [language] that uses this regex safely (null check, error handling). Also provide a version for any major dialect differences (e.g., PCRE vs RE2).